Microscope barlow lenses explained
Named after English mathematician Peter Barlow, a Barlow lens is simply an extra lens you fit over your microscope to increase or decrease the magnification. Having the option to adjust your magnification on the fly can be very handy – it increases the range of magnifications you have access to without needing to buy new eyepieces or a new microscope. But the real value of a Barlow lens lies in what else you can change when you alter your magnification – the field of view and the working distance.